As a core facility, the Morphological Studies Core will continue to be a resource for this competitive renewal of the Program Project. Its function is to provide documentation of the gross and histological findings of the knee joint specimens studied by the respective projects. This descriptive information will be correlated with the specific measurements of each project, providing a multidisciplinary analysis of age-related changes in human knee joint tissue. The Specific Aims of the Morphology Core are: A) Harvest knee joints and perichondrium at autopsy from donors of both genders, all races and all decades from the second to the ninth. B) Make observations and classify and degenerative changes in human knee joints obtained from both genders and all age groups at the time of autopsy. The classification score developed in our laboratories will be utilized to quantify gross morphological changes. C) Harvest cartilage from human knee joints obtained at autopsy for distribution to the tissue culture core. Perichondrial tissue will be provided for projects 2 and 4 and the tissue culture core. D) Take representative osteochondral sections from the human knee joints for processing and assessment using qualitative observations and quantitative histomorphometric measurements using an image analysis system recently developed. Parameters to be measured by histomorphometry are: cartilage roughness, cell count and cell density, and safranin 0 density. In addition, the thickness of the osteochondral plate will be measured and its density will be determined by obtaining microradiographs of the cut slabs using a Faxitron x-ray unit, and comparing the bone density with an aluminum step wedge control. E) Interpret the results of the measurements on the osteochondral sections, and correlate these results with measurements obtained from the other grant projects.